Celestia Forums

I'm very impressed of the Realistic earth dds-textures from Don Edwards. So I've downloaded the whole set of textures. I want to use the 16K/8K for chopping them down in small pieces for Virtual Textures. The 2K and 4K versions for normal use.
The 8/16K are far too huge for my machine for Celestia to work properly but at least I've tried once. Unfortunatly all these textures show very blocky oceans with Celestia.
The 2/4k version look ok with Adobe Photoshop. While loading the 8/16K dds-textures into Photoshop I'll get an error(???), so I'm not sure about these versions.
I don't know how to get a screencapture of this phenomena on a public server to show what I mean.( where to find a public server)

Celestia version: build from the latest files from CVS from a few days ago.

WinXp 750MHz 512Mb ram
nVidia gForce MX400 32Mb driver version 43.45


HB

This is a known glitch and will be fixed in a future release. There color blocks you are speaking of are artifacts left over from when the texture was based on Space-Graphics Render Earth texture that I used as a builing block. I did the same with the 16k texture and unfortunatly that blockiness came along for the ride. I should be able to get this cleared out in the next release if there is one at his point.

Don.

Thanks Don for the explanation. After your relaxing period, I'm looking forward to hear from you again.

Hi HB,

What you see is the well known but never by Nvidea documented DXT1 compression hardware bug. It seems that no one like to speak about own mistakes. This bug concern so far I know all Geforce cards except the FX cards. My current thinking after i learned more about dxt compression is that this Geforce chips use only 8 bit instead 16 bit color depth for the base colors with DXT1 compression. I think you can unterstand that a 8bit (theoretical maximal 9,5 bit) picture looks ugly compared with a 16 bit one. There is only on solution use DXT3 or DXT5 compression.

Bye Jens

p.s. If you want see the bug build a dxt1 and dxt3 version of the same texture and see the diffences in Celestia. Note the compression is for both the same dxt3 has only an additional alpha channel!